Intelligence and Miscellaneous Articles. 431 



rendering a sound distinct always corresponds, notwithstanding the 

 variations of atmospheric pressure *. 



Every possible means have been adopted for verifying the conse- 

 quences of the principal facts which have been announced above, 

 and the greatest care and attention must be paid to the determina- 

 tion of the ventral segments of vibration. It was by piercing or 

 cutting the pipe that the author has succeeded in determining the 

 points at which the air retains its natural state throughout the entire 

 time of vibration. He has thus ascertained that the two open ex- 

 tremities of the pipe are always ventral segments, and that the part 

 near the mouthpiece may be comprised between two or between one 

 node and one- ventral segment. It is possible without Altering the 

 sound to remove the whole of that portion of the tube situated above 

 the extreme wave. 



In the series of sounds represented by the formula which charac- 

 terizes closed pipes, the half- wave near the acoustic orifice is always 

 comprised within two ventral segments; this circumstance sufficiently 

 distinguishes this series from those of Bernoulli. 



In addition to the remarkable fact, that a column of air comprised 

 between two ventral segments without interposition of a node gives 

 a deeper sound than the fundamental sound determined by. its length, 

 the author states that the exceptional wave may sound under two 

 very different pressures ; the "greatest is necessary to produce the 

 sound when the pipe is restored to its original length. 



In all the experiments the volume of the reservoir of air or the 

 conduit pipe was changed several times without any recognizable 

 alteration in the phenomena being produced. 



All pipes, whatever their dimensions of material, conform to the 

 same laws. Pipes of wood, gutta percha, glass and metal were em- 

 ployed ; the ratio of the length and diameter has varied from 4 to 

 40, and no exceptions to the principles laid down by the author were 

 met with. 



By placing the acoustic orifice between two tubes of the same 

 diameter and length which bear a simple proportion to each other, 

 it was found that the two columns vibrated in unison when by their 

 division they were capable of giving rise to subdivisions of the same 

 length, the exceptional parts situated at each side of the plate being 

 equal to each other or to an octave. In every other case the note of 

 one pipe alone is heard. — Comptes Rendus, Feb. 1853. 



OBSERVATIONS ON SOME EFFECTS PRODUCED BY ELECTRIC 

 CURRENTS. BY A. MASSON. 



In producing the decomposition of water with the ingenious 

 apparatus of M. Ruhmkorff, Mr. Grove f found the extremities of 

 the Wollaston conductors perfectly luminous ; like his predecessor, 

 he obtained detonating mixtures at both poles, sometimes with an 



* TJie practical value of these principles has already been shown in a 

 work, published by M. Louyet and the author, upon the theory of wind 

 instruments and of the voice (Traite de Physiologie, par F. A. Louyet, 

 tome i. fasicule 3). 



t Phil. Mag. March 1853. 



